Listening to a baby breathing at night can be pretty scary. At times it can be very loud and irregular and other times almost silent. With my first child I stayed up many nights stressing over this, so my motivation for this project was to let me sleep in peace knowing my soon to be delivered (at the time) 2nd child was being carefully monitored. As it turned out, the stress went away with my second child and I am able to sleep like a baby (while the baby is sleeping) even without the monitor. This is good as the Baby Monitor project wasn't a complete success (as described in the project documentation). In any case, I think it makes for a good proof of concept and wanted to share the results.
This project uses the Texas Instruments eZ430-Chronos development kit watch that features, among other things, an RF transceiver and USB access point to allow the watch to wirelessly communicate with a computer, a low cost 3-axis accelerometer and a temperature sensor. The idea for this project was simply to modify the watch's software and write a Python based computer application to wirelessly monitor a baby's orientation (to make sure it is sleeping on it's back for SIDS prevention), temperature, and movement (from breathing) as the baby sleeps, and report alarms if the baby is to roll over onto its belly, stop breathing, or get too hot or too cold.
Baby Monitor Project Documentation (PDF)
Python PC Baby Monitor Script (Zip)
Firmware - Uses Free TI Code Composer Studio IDE (Zip)